This invention relates generally to improvements in "analog" wristwatches which are illuminated for telling time in the dark. More particularly, the invention relates to an improved electroluminescent watch dial support and connector assembly, and is an improvement on U.S. Pat. No. 4,775,964 entitled "Electroluminescent Dial for An Analog Watch and Process for Making It" issued Oct. 4, 1988 and assigned to applicants' assignee said patent being incorporated herein by reference.
Assignees' U.S. Pat. No. 4,775,964 disclosed an electroluminescent dial for an analog watch. Under normal daytime viewing conditions, time-indicating indicia printed on the dial are read in conjunction with one or more time indicating hands. The electroluminescent dial comprised a transparent substrate having time-indicating indicia printed on the upper surface and electroluminescent material on its undersurface with an actuating circuit within the timepiece to cause the dial to be uniformly illuminated. The preferred embodiment shown in the patent comprised a rigid self-supporting substrate with conductive layers on either side of the electroluminescent material. Electrical connections to the circuit were provided by a conductive adhesive for attaching the leads to the conductive layers.
The aforesaid patent also disclosed a flexible electroluminescent dial wherein the substrate comprised commercially available Mylar film coated with electrically conductive indium tin oxide (ITO). While a flexible electroluminescent dial offers many advantages, it has been found that excessive flexing or bending may tend to introduce microscopic cracks in the ITO layer causing electrical discontinuities. Furthermore, because of the close tolerances and small clearances in a wristwatch, excessive movement or shifting of a flexible dial may interfere with proper operation of the timepiece.
Accordingly, one object of the present invention is to provide an improved support and connector assembly for an electroluminescent watch dial.
Another object of the invention is to provide an improved construction for supporting a flexible electroluminescent dial for an analog watch.
Still another object of the invention is to provide an improved connector assembly for making electrical connections between the electroluminescent dial and the electrical circuit actuating the electroluminescent layer.